Clever, especially in a dishonest or secret way. (Cambridge Dictionary)
Skillful in underhand or evil schemes; cunning; deceitful; sly. (Dictionary.com)
Adept in the use of subtlety and cunning. (Merriam – Webster)
Marked by subtlety and guile. (Merriam – Webster)
If you describe someone as crafty, you mean that they achieve what they want in a clever way, often by deceiving people. (Collins Dictionary)
Treacherous and crafty.